ntp: Add skeleton for Simple NTP support

1 files changed, 382 insertions, 0 deletions

diff --git a/src/ntp.c b/src/ntp.c
new file mode 100644
index 00000000..32ae714d
--- /dev/null
+++ b/src/ntp.c
@@ -0,0 +1,382 @@
+/*
+ *
+ *  Connection Manager
+ *
+ *  Copyright (C) 2007-2010  Intel Corporation. All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+
+#include <glib.h>
+
+#include <gweb/gresolv.h>
+
+#include "connman.h"
+
+struct ntp_short {
+	uint16_t seconds;
+	uint16_t fraction;
+} __attribute__ ((packed));
+
+struct ntp_time {
+	uint32_t seconds;
+	uint32_t fraction;
+} __attribute__ ((packed));
+
+struct ntp_msg {
+	uint8_t flags;			/* Mode, version and leap indicator */
+	uint8_t stratum;		/* Stratum details */
+	int8_t poll;			/* Maximum interval in log2 seconds */
+	int8_t precision;		/* Clock precision in log2 seconds */
+	struct ntp_short rootdelay;	/* Root delay */
+	struct ntp_short rootdisp;	/* Root dispersion */
+	uint32_t refid;			/* Reference ID */
+	struct ntp_time reftime;	/* Reference timestamp */
+	struct ntp_time orgtime;	/* Origin timestamp */
+	struct ntp_time rectime;	/* Receive timestamp */
+	struct ntp_time xmttime;	/* Transmit timestamp */
+} __attribute__ ((packed));
+
+#define OFFSET_1900_1970  2208988800UL	/* 1970 - 1900 in seconds */
+
+#define STEPTIME_MIN_OFFSET  0.128
+
+#define LOGTOD(a)  ((a) < 0 ? 1. / (1L << -(a)) : 1L << (int)(a))
+
+static struct timeval transmit_timeval;
+static char *transmit_server;
+static int transmit_fd;
+static guint transmit_delay = 16;
+
+static void send_packet(int fd, const char *server)
+{
+	struct ntp_msg msg;
+	struct sockaddr_in addr;
+	ssize_t len;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.flags = 0x23;
+	msg.poll = 4;	// min
+	msg.poll = 10;	// max
+	msg.xmttime.seconds = random();
+	msg.xmttime.fraction = random();
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(123);
+	addr.sin_addr.s_addr = inet_addr(server);
+
+	gettimeofday(&transmit_timeval, NULL);
+
+	len = sendto(fd, &msg, sizeof(msg), MSG_DONTWAIT,
+						&addr, sizeof(addr));
+	if (len < 0) {
+		connman_error("Time request for server %s failed", server);
+		return;
+	}
+
+	if (len != sizeof(msg)) {
+		connman_error("Broken time request for server %s", server);
+		return;
+	}
+}
+
+static gboolean next_request(gpointer user_data)
+{
+	DBG("server %s", transmit_server);
+
+	send_packet(transmit_fd, transmit_server);
+
+	return FALSE;
+}
+
+static void decode_msg(void *base, size_t len, struct timeval *tv)
+{
+	struct ntp_msg *msg = base;
+	double org, rec, xmt, dst;
+	double delay, offset;
+
+	if (len < sizeof(*msg)) {
+		connman_error("Invalid response from time server");
+		return;
+	}
+
+	if (tv == NULL) {
+		connman_error("Invalid packet timestamp from time server");
+		return;
+	}
+
+	DBG("flags      : 0x%02x", msg->flags);
+	DBG("stratum    : %u", msg->stratum);
+	DBG("poll       : %f seconds (%d)",
+				LOGTOD(msg->poll), msg->poll);
+	DBG("precision  : %f seconds (%d)",
+				LOGTOD(msg->precision), msg->precision);
+	DBG("root delay : %u seconds (fraction %u)",
+			msg->rootdelay.seconds, msg->rootdelay.fraction);
+	DBG("root disp. : %u seconds (fraction %u)",
+			msg->rootdisp.seconds, msg->rootdisp.fraction);
+	DBG("reference  : 0x%04x", msg->refid);
+
+	transmit_delay = LOGTOD(msg->poll);
+
+	if (msg->flags != 0x24)
+		return;
+
+	org = transmit_timeval.tv_sec +
+			(1.0e-6 * transmit_timeval.tv_usec) + OFFSET_1900_1970;
+	rec = ntohl(msg->rectime.seconds) +
+			((double) ntohl(msg->rectime.fraction) / UINT_MAX);
+	xmt = ntohl(msg->xmttime.seconds) +
+			((double) ntohl(msg->xmttime.fraction) / UINT_MAX);
+	dst = tv->tv_sec + (1.0e-6 * tv->tv_usec) + OFFSET_1900_1970;
+
+	DBG("org=%f rec=%f xmt=%f dst=%f", org, rec, xmt, dst);
+
+	offset = ((rec - org) + (xmt - dst)) / 2;
+	delay = (dst - org) - (xmt - rec);
+
+	DBG("offset=%f delay=%f", offset, delay);
+
+	if (offset < STEPTIME_MIN_OFFSET && offset > -STEPTIME_MIN_OFFSET) {
+		struct timeval adj;
+
+		adj.tv_sec = (long) offset;
+		adj.tv_usec = (offset - adj.tv_sec) * 1000000;
+
+		DBG("adjusting time");
+
+		if (adjtime(&adj, &adj) < 0) {
+			connman_error("Failed to adjust time");
+			return;
+		}
+
+		DBG("%lu seconds, %lu msecs", adj.tv_sec, adj.tv_usec);
+	} else {
+		struct timeval cur;
+		double dtime;
+
+		gettimeofday(&cur, NULL);
+		dtime = offset + cur.tv_sec + 1.0e-6 * cur.tv_usec;
+		cur.tv_sec = (long) dtime;
+		cur.tv_usec = (dtime - cur.tv_sec) * 1000000;
+
+		DBG("setting time");
+
+		if (settimeofday(&cur, NULL) < 0) {
+			connman_error("Failed to set time");
+			return;
+		}
+
+		DBG("%lu seconds, %lu msecs", cur.tv_sec, cur.tv_usec);
+	}
+}
+
+static guint channel_watch = 0;
+
+static gboolean received_data(GIOChannel *channel, GIOCondition condition,
+							gpointer user_data)
+{
+	unsigned char buf[128];
+	struct msghdr msg;
+	struct iovec iov;
+	struct cmsghdr *cmsg;
+	struct timeval *tv;
+	char aux[128];
+	ssize_t len;
+	int fd;
+
+	if (condition & (G_IO_HUP | G_IO_ERR | G_IO_NVAL)) {
+		connman_error("Problem with timer server channel");
+		channel_watch = 0;
+		return FALSE;
+	}
+
+	fd = g_io_channel_unix_get_fd(channel);
+
+	iov.iov_base = buf;
+	iov.iov_len = sizeof(buf);
+
+	memset(&msg, 0, sizeof(msg));
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+	msg.msg_control = aux;
+	msg.msg_controllen = sizeof(aux);
+
+	len = recvmsg(fd, &msg, MSG_DONTWAIT);
+	if (len < 0)
+		return TRUE;
+
+	tv = NULL;
+
+	for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+		if (cmsg->cmsg_level != SOL_SOCKET)
+			continue;
+
+		switch (cmsg->cmsg_type) {
+		case SCM_TIMESTAMP:
+			tv = (struct timeval *) CMSG_DATA(cmsg);
+			break;
+		}
+	}
+
+	decode_msg(iov.iov_base, iov.iov_len, tv);
+
+	g_timeout_add_seconds(transmit_delay, next_request, NULL);
+
+	return TRUE;
+}
+
+static void start_ntp(const char *server)
+{
+	GIOChannel *channel;
+	struct sockaddr_in addr;
+	int fd, tos = IPTOS_LOWDELAY, timestamp = 1;
+
+	DBG("server %s", server);
+
+	if (channel_watch > 0)
+		return;
+
+	fd = socket(PF_INET, SOCK_DGRAM, 0);
+	if (fd < 0) {
+		connman_error("Failed to open time server socket");
+		return;
+	}
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+
+	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		connman_error("Failed to bind time server socket");
+		close(fd);
+		return;
+	}
+
+	if (setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) {
+		connman_error("Failed to set type of service option");
+		close(fd);
+		return;
+	}
+
+	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &timestamp,
+						sizeof(timestamp)) < 0) {
+		connman_error("Failed to enable timestamp support");
+		close(fd);
+		return;
+	}
+
+	channel = g_io_channel_unix_new(fd);
+	if (channel == NULL) {
+		close(fd);
+		return;
+	}
+
+	g_io_channel_set_encoding(channel, NULL, NULL);
+	g_io_channel_set_buffered(channel, FALSE);
+
+	g_io_channel_set_close_on_unref(channel, TRUE);
+
+	channel_watch = g_io_add_watch_full(channel, G_PRIORITY_DEFAULT,
+				G_IO_IN | G_IO_HUP | G_IO_ERR | G_IO_NVAL,
+				received_data, NULL, NULL);
+
+	g_io_channel_unref(channel);
+
+	transmit_fd = fd;
+	transmit_server = g_strdup(server);
+
+	send_packet(fd, server);
+}
+
+static void resolv_debug(const char *str, void *data)
+{
+	connman_info("%s: %s\n", (const char *) data, str);
+}
+
+static GResolv *resolv = NULL;
+static guint resolv_lookup = 0;
+
+static void resolv_result(GResolvResultStatus status,
+					char **results, gpointer user_data)
+{
+	int i;
+
+	resolv_lookup = 0;
+
+	if (results != NULL) {
+		for (i = 0; results[i]; i++)
+			DBG("result: %s", results[i]);
+
+		if (results[0] != NULL)
+			start_ntp(results[0]);
+	}
+}
+
+int __connman_ntp_start(const char *interface, const char *resolver,
+							const char *server)
+{
+	DBG("interface %s server %s", interface, server);
+
+	resolv = g_resolv_new(0);
+	if (resolv == NULL)
+		return -ENOMEM;
+
+	if (getenv("CONNMAN_RESOLV_DEBUG"))
+		g_resolv_set_debug(resolv, resolv_debug, "RESOLV");
+
+	if (resolver != NULL)
+		g_resolv_add_nameserver(resolv, resolver, 53, 0);
+
+	g_resolv_lookup_hostname(resolv, server, resolv_result, NULL);
+
+	return 0;
+}
+
+void __connman_ntp_stop(const char *interface)
+{
+	DBG("interface %s", interface);
+
+	if (resolv == NULL)
+		return;
+
+	if (resolv_lookup > 0) {
+		g_resolv_cancel_lookup(resolv, resolv_lookup);
+		resolv_lookup = 0;
+	}
+
+	if (channel_watch > 0) {
+		g_source_remove(channel_watch);
+		channel_watch = 0;
+	}
+
+	g_resolv_unref(resolv);
+}